Apparatus for burnishing silver plate



y 7, 1931- TRINQUET ET AL 1,312,909

APPARATUS FOR BURNISHING SILVER PLATE Filed Jul-y 5, 1928 4 Sheets-Sheet. l

- MJ WM I VVE 7' iS 0 WW 0% July 7, 1931. TRINQUET ETAL APPARATUS FOR BURNISHING SILVER PLATE Filed July 5, 1928 4 Sheets-Sheet. 2

July 7, 1931. TRINQUET ET AL APPARATUS FOR BURNISHING SILVER PLATE Filed July 5, 1928 4 Sheets-Sheet a July 7 1931. TRINQUET ET AL 1,812,909

APPARATUS FOR BURNISHING SILVER PLATE Filed July 5, 1928 4 Sheets-Sheet, 4

Patented July 7, 1931 STATES PATENT QFFIE Louis TRINQUET, or PYAVILLON S/BOIS, AND RENE MARCEL I-IAMEL, on ST. OUEN,

FRANCE APPARATUS FOR BURNISI-IING SILVER PLATE Application filed. July 5, 1928, Serial No. 290,677, and in France July 12, 1927.

; Silver plate and the like is generally burnished by hand or in a cask. The hand process provides good finish but shows the drawback of requiring a large handicraft where by it lacks efficiency and cheapness. The other process according to which the objects to be burnished are placed in a cask containing metal balls which is rotated, gives poor results and it is necessary togive a finish by hand. Moreover the objects are often deformed and must be set straight again.

The work afforded by hand burnishing is perfect, because the burnishing tool strongly pressed against the object is given a small reciprocating motion and maybe brought by the hand against all the parts of the surface to be burnished.

Now our invention has for its object a me chanical burnishing and polishing method providing substantially the same conditions of work and a machine for executing said method. This method is characterized by the fact that the object to beburnished or polished is submitted to the action of a rotary tool made of suitable material and provided with oblique working ribs.

*It is easy to understand that when an object is brought against the. top of such a rotary tool the point of contact between it and the oblique working ribwill move substantially parallel with the axis of the tool. This point providingthe burnishing-tool will thus execute, over the surface to be burnished or to be polished the same reciprocating. mo-

tion as the usual hand controlled burnishing tool whereby the work obtainedposseses the same perfection.

- Of course each tool and its working. ribs should have a shape adapted to that of the is easy to determine in each case.

For instance in the case' of a convex surface, the tool will. be given the shape show-n on Fig.7 i. e. substantially cylindrical form provided throughout itsmiddle circumference with a groove widening from zero to the whole height of the cylinder and narrowing again down to zero towards its starting point.

If a convex surface'the convexity of which is 40 surface which the tool is to work. i This shape to smaller than the depth of the groove is disposed over such a tool, it will be in contact with it only through the working ribs formed by the edges of the groove.

Similarly a tool for working on a concave surface should be given the shape shown on 5 Fig. 5, i. e. that of an egg, the central part of which is alone retained between the two oblique working ribs starting together from a point of the largest cross section, passing respectively over the upper and lower part of the egg and meeting suddenly towards their starting point, the partof the egg outside the ribs being removed. vVhen a concave surface the concavity of which is greater than the projection of the tool beyond its ribs is brought over this tool it will only bear against the ribs.

In both of the preceding cases, which correspond for instance to the burnishing of the outside and of the inside of a spoon, when the tool bears against the spoon through the surface where the two ribs meet, the spoon is burnished in its middle. hen the tool rotates the two working points move first apart and then against each other and so forth.

Having thus disclosed the principle underlying our invention we may add that in ad dition to the rotary motion of the tool, the object to be treated which is yieldingly pressed against the tool is caused to move substantially perpendicularly with reference to the axis of rotation of the tool whereby the latter may Work successively over different surfaces of the object. At the same time the latter is, if required, lifted vertically i. e. perpendicularly to both the axis of the tool and the direction of movement of the object and caused to pivot round a horizontal axis i. e. parallel to the axis of the tool so as to bring successively in front of the tool the different parts of the surface of the object in substantial tangent relationship.

Another object of our invention relates to a machine for executing the above described method and adapted chiefly for burnishing covers. In this machine the spoon or fork is held down by a. device which submits it automatically with the desired pressure to the rotary tools which are to burnish its different parts.

We have described hereinbelow and shown in accompanying drawings several forms of execution of the tools and one form of execu tion of the machine.

Fig. 1 shows a tool for very concave objects and Fig. 2 shows the ribs thereof developed on a plane.

Fig.3 shows for two different angular positions a tool for burnishing the teeth of forks and F ig. 4 shows the ribs thereof de-- veloped on a plane.

' chine for burnishing covers.

v .to engage The tool of Figs. 1 and 2 is constitutedby a cylindrical core provided with a torus sha' ed aro'ection of which only those arts P i l P 1 are retained which are disposed between the two working ribs arranged substantially in two oblique planes equally inclinedin opposite directions with reference to the cross section of the cylinder.

If aconcave surface, the concavity of which is greater than the convexity of the toric parts 1, is applied against this tool. it will come in contact with it only through its working ribs. points on the two ribs will reciprocate between the middle planeof the tool and its ends; thus the cross section of the concave surface in front of the tool will be burnished and the'object being moved progressively in a direction perpendicular to the axis of the tool will be burnished throughout.

The tool shown on Figs. 3. and dis sub- 7 stantially cylindric and has two oblique working ribs 4 raised above the surface 3. These ribs start from a common point on the. middle cross-section of thetool and end at the opposite edges thereof at points disposed near the eneratrix aassin through the startin point. V

' This tool is adapted to burnish forkteeth. WVhen the tool is incontact with the fork through the starting point of the two ribs appearing on the outline of the tool on the right hand part of Fig. 3 this sort of projection passes between the two central teeth of the fork and burnishes the inside thereof. Then working points on the two ribs are sufiicient' ly spaced for the said ribs which have a very small obliquity with reference to the teeth, respectively between one of the middle teeth and the corresponding outer tooth whereby the gaps'betweenthese teeth Whilst the tool rotates the working r are burnished; the contact points moving still further apart burnish the underside of the outer teeth and lastly the outside of the outer teeth are burnished.

The shape and the manner of working of the tools shown on Figs. 5, 6 and 7 8 adapted to burnish the inside and the outside of spoons have already been described at the beginning of this specification. The tool shown on Figs.

5-6 is preferably mounted on a spindle passing through the eccentric holes 56 whereby the spoon need not oscillate with too great an amplitude between the positions where it bears through its middle on the parts of the'two ribs which are near each other and that where it bears through its/edges on the parts thereof which are the furthest apart.

The machine comprises mainly a table 10 bearing a braoketll between the uprights of which are disposed the burnishing tools which in the example shown are intended for burnishing a spoon and consist in a lower tool 5 for burnishing the inside of the spoon and an upper tool 8 for burnishing its outside.

The tool 5 is mounted on a spindle 12 secured to a transversal shaft 13 to the end of which is keyed a bevel pinion 14 meshing with a second bevel pinion 15 secured to the same shaft as the bevel pinion 16 meshing with the control bevel pinion 17 borne by the shaft 18. This shaft may be actuated through a clutch 19 controlled by the knob 20 (Fig. 11) through the rod 21 and the bell crank 22 pivoting round 23. V

To the shaft 13 is keyed a straight pinion 2 1 meshing with a toothed wheel 25 secured to the shaft 26 which drives through two universal links 27 28 and the rod 29 a stub shaft 30 to which is secured the uppertool 8. This tool is securedto the frame 31 disposed inside the bracket 'lland urged downwards by the spring 32 the pressure of which may be adjusted by a cam borne by the handle 33. The bracket 11 may moreover rock round shaft 12 and its inclinewith reference to said shaft may be modifiedas explained hereinafter by the stop 49. Thus it is apparent that the upper tool is always applied tangentially against the spoon or other object and that the said object to be treated is held with sufficient pressure between the two tools. 1

Of course the stub shaft 30 passes through suitable slots in the uprights of the bracket 11 and the shaft 12 also passes through slots 1 provided in the sides of the frame 31.

The spoon'not shown is held moreover by its handle in the jaws 34 (Figs. 10 and 11) the tightening of which is controlled by the cam-bearing lever 35. These jaws are provided with an extension36 adapted to pivot round the horizontal spindle 37 borne by a rod 38 slidably secured in the part 39 to which it is fastened by means of the screw 40. The part3?) may also slide vertically in the socket 41 with reference to which it is'secured by the set screw 42. Thesocket .41 is borne by a carriage .43 sliding in suitable slides on the table 19. The carriage 43 is secured to a nut shaped part 44' screwed over the threaded rod 45 parallel to the surface of the table. To the end of this rod is secured a toothed wheel 46 meshing witha worm 47 mounted on the shaft 48 V which is caused to rotate through the clutch 19.

A stop 49 carried by the carriage 43 acts on dampers 50 carried by the oscillating frame 11 andmodifies the incline of'the latter according to the longitudinal position of the sprfeln so o make the tool move in accordance with the shape of the spoon. The bracket is urged against this stop by the tension spring 51.

to have only one Thus whilst the tools 5 and 8 rotate the spoon moves automatically with reference thereto. When the body of the spoon is burnished the tools may be changed for operation on the handle or still better in order to avoid the change of tools the spoon may be removed after releasing the spring 32 through the lever 33 and brought to another machine provided with the required tools. Thus by using a number of machines equal to that of the parts requiring different tools, a considerable output per hour may be obtained.

Of course the above described form of execution of the machine is given only by way of example and numerous modifications may be brought thereto without affecting the scope of the invention. Thus the threaded rod 45 may be replaced by a connecting link and the toothed wheel 46 by a cam, a crank or an eccentric. The carriage and the parts borne thereby will therefore be given a reciprocating movement at the desired speed whilst the tools are given a very slow rotation throu a a suitable demultiplying worm gears replacing V the bevel pinions 14-15 and 1647.

WVhat we claim is:

1. A machine for mechanically burnishing and polishing objects chiefly covers comprisa rotary tool, oblique working ribs provided thereon, means for yieldingly pressing the tool to bear tangentially through its working ribs against the object to be'treated, means for shifting the angular position of the said means with reference to the axis of rotation of the tool and means for making the object advance in a direction perpendicular to the axis of rotation of the tool.

2. A device for the mechanical burnishing of covers and similar objects including a rotary tool provided with ribs of approximately screw thread form adapted at each moment point of contact with the surface of the object to be polished, which point of contact is displaced during the polishing substantially parallel to the axis of rotation of the tool, means to effect continuous rotation of the tool, means for bringing and maintaining an object to be polished yieldingly in contact with the polishing ribs of the tool, means adapted to displace the object to be polished longitudinally substantially perpendicularly to the axis of rotation of the tool.

3. A device for the mechanical burnishing of covers and like objects including a rotary tool provided with two polishing ribs formed symmetrically relative to the plane of syn metry of the tool which is perpendicular to its axis, said ribs starting-from the plane of symmetry from which they are gradually removed,- the ribs being approximately of screw thread form and adapted at each moment to have only one point of contact with the sun face of an object to be polished, which point of contact is displaced during polishing substantially parallel to the axis of rotation of the tool, means for effecting continuous r0- .tation of the tool, means for bringing and maintaining the object to be polished yieldingly in contact with the polishingribs of the tool, and means adapted to displace the object to be polished longitudinally substantially perpendicularly to the axis of rotation of thetool.

4. A device for the mechanical burnishing of covers and similar objects comprising a rotary toolon which two polishing ribs are formed symmetrically relative to the plane of symmetry of the tool which is perpendicular to its axis, the said ribs'both starting from this plane of symmetry from which they are gradually removed, thefrihs then approaching the said plane of symmetry for being reunited there, the ribs being formed in such a manner that each of them, approximately in the form of a screw thread, has at each moment only one point of contact with the surface of the objectto be polished which is displaced during the polishing substantially parallel'to the axis of rotation of the tool,'. means adapted to cause the tool to rotate in a continuous manner, means for bringing and maintaining the object to be polished yieldingly in contact with the polishing ribs of the tool, means adapted to displace the piece to be polished. longitudinally substantially perpendicularly to the axis of rotation of the tool.

device for the mechanical burnishing of covers and similar objects comprising a rotary tool on which polishing ribs are formed in such a manner that each of them, approximately in the form of a screw thread, has at each moment only one point of contact with the surface of the object to be polished which point of contact is displaced during the polishing almost parallel to the axis of rotation of the tool. means adapted to cause tho toolto rotate in a continuous manner means for bringing and maintaining the obectto be polished yieldin gly in contact with the polishing ribs'of the tool, means adapted to di lace the object to be polished longi- I to the axis of rotation of the tudinally almost perpendicularly to the axis rotation of the tool, means adapted to modify the angle formed by the axis of the v object to be polished with the axis of the tool; 6. A device for the mechanical burnishing of covers and similar objects comprising a 'rotarytool on which polishing ribs are formed in such a manner that each of them, approximately in the form of a' screw thread, has at each moment'only one point ofcontact with the surface of the object to be polished which point of contact is displaced during the polishing approximately parallel to the axis of rotation of the tool, means adapted to cause the tool to rotate in a continuous manner, acarriage adapted to carry the object to be polished and to bring and maintain it yieldingly in contact with the tool, a

longitudinal guide'for the carriage, means adapted to control the displacement of the carriage along the guide so as to displace the object'to be polished almost perpendicularly tool.

7. A device for the mechanical burnishing of covers and similar objects comprising two rotary tools on both sides of the location of the object to be polished, the axes of rotation of which are parallel, polishing ribs being formed on each of the tools in'such a manner that each of the ribs approximately in the form of a screw thread has at each moment only one point of contact with the surface of the'object to be polished which point of contact isldispla ced during. the polishing substantially parallel to the axis of rotation of the tool means adapted'to cause the tools to rotate in a continuous manner, a carriage adapted to carry the object to be polished and to maintain same between thetwo tools and in contact with these tools, a longitudinal guide forthe carriage, means adapted to control the displacement of the carriage along the guide so as to displace the object to be polished almost perpendicularly to the axes of rotation of the rotary tools.

device for the mechanical burnishing of covers and similar objects comprising two rotary tools on both sides of the location of the object to be polished, the axes of rotation of which are parallel, polishing ribs being formed on each of the tools in such a manner that each of the ribs approximately vin the form of a screw thread-has at each moment only one point of contact with the surface of the object to be polished which point of contact is displaced during the polishing approximately parallel to the axisofrotaltion of the tool, spindles forming the axes of the two fixed tools, bearings supporting one of the spindles, a frame on which the spindle of the other tool is mounted and adapted to ro tate, a driving spindle connected by universal joints to the spindle of the latter tool, a

bracket for this driving spindle mounted so I as to be pivotally regulated-around the driving spindle mounted infixed bearings, means for controlling the rotation of the tool mounted in the fixed bearings, a carriage adapted to carry the object to be polished be tween the tools, a longitudinal guide for the carriage, means adapted to control the displacement of the carriage along the guide so as to displace the piece to be polished almost perpendicularly to the axis of rotation of the tool. 7

In testimony whereof we have afiixed our signatures.

LOUI S TRINQUET.

RENE MARCEL HAMEL. 

